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US president Barack Obama today welcomes arguably his least favourite foreign leader to the White House. Israeli prime minister Benjamin Netanyahu's visit neatly coincides with the annual policy conference of the American Israel Public Affairs Committee (Aipac). That event offers both men a chance to appeal to some of Israel's most ardent American supporters. We can therefore expect to hear repeated references to the "common interests", "unshakeable bonds" and "shared values" of the two countries.

This familiar rhetoric is misleading at best and at worst simply wrong. No states have identical interests, and Israel and America are at odds on two vital issues: Iran and the Israeli-Palestinian conflict. Mr Obama should continue to rebuff Israel's efforts to push him into military confrontation with Tehran, while reminding Mr Netanyahu the true danger to Israel lies in its refusal to allow a viable Palestinian state.

On Iran, Mr Netanyahu is convinced it wants nuclear weapons, and that this goal threatens Israel's existence. He does not think diplomacy can stop Iran, and wants the US to destroy its nuclear facilities. If Mr Obama refuses to order an attack, the Israeli leader would like a green light to do so.

Mr Obama and his advisers — including the military — see things differently. They do not want Iran to obtain nuclear weapons, but they do not believe a nuclear-armed Iran would pose an existential threat to Israel. After all, Israel has its own nuclear arsenal, and could obliterate Iran if attacked. US intelligence is also confident Tehran has not yet decided to build nuclear weapons. Indeed, US leaders worry that, no matter who does it, an attack would convince Iran it needs its own nuclear deterrent. They are correct.

Equally important, force cannot produce a meaningful victory. Israel's air force cannot destroy all Iran's nuclear facilities; even a successful US attack could not eliminate the knowledge on which the programme is based. Iran would simply rebuild its facilities in less vulnerable locations, as Iraq did after Israel bombed the Osirak reactor in 1981.

In short, while one can understand why Israeli hardliners might want the US to strike Iran, Washington has no interest in pursuing this course and Mr Obama should make this crystal clear to Mr Netanyahu.

The gulf between Washington and Jerusalem is just as wide on the Palestinian issue. Mr Netanyahu opposed the 1993 Oslo accords, which sought to resolve the conflict and establish Palestinian self-rule. The only "state" he would countenance today is a set of disconnected and disarmed enclaves under de facto Israeli control. He was elected in 2009 on a platform rejecting Palestinian statehood, and his cabinet is populated with politicians who want to control the West Bank forever. His government continues to expel Palestinians from their homes in Jerusalem and the West Bank, and to expand Israeli settlements there.

By contrast, Mr Obama is committed to helping create a viable Palestinian state living alongside Israel in peace. As he said in Cairo in June 2009, a two-state solution is "in Israel's interest, Palestine's interest, America's interest, and the world's interest". He knows the combination of US support for Israel and Israel's treatment of the Palestinians fuels anti-Americanism throughout the Arab and Islamic world, and contributes to the global terrorism problem.

In fact, the Palestinian issue is the real existential threat to Israel. More than 500,000 Israeli Jews now live in the occupied territories, and continued settlement building will lead to a single state between the Jordan river and the Mediterranean sea. Given demographic trends, this "Greater Israel" could not be both a Jewish state and a full democracy. Instead, it would be an apartheid state, threatening Israel's legitimacy and long-term survival. As Ehud Olmert, former prime minister, said in 2007, if the two-state solution fails, Israel "will face a South African-like struggle for equal voting rights". And if that happens, he warned, "the state of Israel is finished".

Mr Netanyahu and Mr Obama have clashed repeatedly on the Palestinian issue, and each time Mr Obama has backed down. He is unlikely to press the issue between now and November's election. Instead, he will act as if the US and Israel remain the closest of allies.

If only this were true. In fact, this situation highlights the dysfunctional nature of the "special relationship". If the US and Israel had a normal relationship, Mr Obama could make his disagreements with Mr Netanyahu plain, and use the bully pulpit and America's substantial leverage to help Israel rethink its course. But Aipac and other groups in the formidable Israel lobby insist politicians admit no daylight between what Israel wants and what Washington says and does. For Mr Obama, acknowledging these obvious strategic differences would alienate crucial political allies, leading Democratic party fundraisers and Israel’s supporters in the media, imperilling his re-election prospects.

Because war entails significant costs and risks, and brings no lasting benefits, the best hope is that Mr Obama will continue to deflect pressure for military action, no matter what he says in public. Meanwhile, the greatest danger to Israel — the occupation — continues unchecked.

The writers are professors at the University of Chicago and Harvard Kennedy School respectively